In dye diffusion transfer recording systems, a heat-sensitive transfer sheet (hereinafter also referred to as an ink sheet) containing colorants (hereinafter also referred to as a dye) is superposed on a heat-sensitive transfer image-receiving sheet (hereinafter also referred to as an image-receiving sheet), and then the heat-sensitive transfer sheet is heated by a thermal head whose exothermic action is controlled by electric signals, in order to transfer the dyes contained in the heat-sensitive transfer sheet to the image-receiving sheet, thereby recording an image information. Three colors: cyan, magenta, and yellow, or four colors which consists of the three colors and black, are used for recording a color image by overlapping one color to other, thereby enabling transferring and recording a color image having continuous gradation for color densities.
On the other hand, in recent years, the demands on color images are diversified, and there is a demand for obtaining three-dimensional images conveniently and inexpensively. It has been known that, so as to make a picture, a photograph or the like to appear stereoscopic, a lenticular lens (sheet-shaped, hereinafter also referred to as a lenticular lens sheet) formed from semi-cylindrical lenses is attached on a printed picture or photograph correspondingly to the right-side eye and the left-side eye. In order to make the picture, photograph, or the like appear stereoscopic with high precision in this technique, it is required that the printed images viewed respectively by the right-side eye and the left-side eye are disposed in correspondence with the positions of the respective lenses of the lenticular lens.
Japanese Patent No. 3609065 discloses an image recording apparatus equipped with a recording unit that records an image on the back side of the lenticular lens sheet; a moving mechanism for moving the recording unit and the lenticular lens sheet relatively to each other; a position detecting unit provided to be contacted with the concave parts and/or convex parts of the lenticular lens sheet; and a recording control unit that controls the recording unit to perform recording while detecting the position of the lenticular lens sheet by means of the position detecting unit.
Japanese Patent No. 3789033 discloses a method for producing a lenticular lens sheet printed material, including: preparing a heat transfer sheet provided with a coloring material transfer unit and a white layer transfer unit in area order on the same surface of a substrate film; thermally moving the coloring material from the coloring material transfer unit to the back surface of the lenticular lens sheet by using a heating device; and subsequently thermally transferring the white layer on the lenticular lens sheet.
JP-A-6-282019 (“JP-A” means unexamined published Japanese patent application) discloses a heat-sensitive transfer recording sheet for stereoscopic photographs, which utilizes a lenticular lens sheet as a substrate and has a dye receptor layer provided on the back side of the lenticular lens sheet.
However, when images are printed using such the lenticular lens sheet and the heat-sensitive transfer image-recording sheet, a transfer failure in the form of white or colored spots occurs in black and high-density image areas. There was posed a new problem that when identical images are printed, the three-dimensional sensation of the images viewed through the lenticular lens may be lowered. These problems are prone to occur under high temperature and high humidity conditions or under low temperature and low humidity conditions, and thus it is strongly demanded to solve these problems.